Air conditioning unit

ABSTRACT

The invention relates to an air conditioning unit ( 1 ), in particular for a stand-alone operation in a motor vehicle, comprising a compressor, condenser ( 3 ) and evaporator ( 2 ) that are situated in a coolant circuit, for cooling the air to be conditioned. According to the invention, the unit is equipped with a single fan ( 5 ) for the air that dissipates the heat and for the cooled air that is to be fed to the interior of the vehicle, said fan transporting part of the air through the condenser ( 3 ) and the other part through the evaporator ( 2 ).

BACKGROUND OF THE INVENTION

The present invention relates to an air conditioning unit for a motor vehicle, especially a commercial vehicle, according to the preamble of claim 1

It is a goal of the vehicle manufacturers to provide the vehicle occupants a comfortable indoor climate even when a vehicle is stationary, especially when the engine is shut off. Standstill air conditioning equipment is increasingly being provided, especially for the commercial vehicle sector.

With very high outdoor temperatures, the increase in comfort for a driver spending the night in a sleeping cabin of a commercial vehicle, for example, is considerable. One design problem is to supply power during idle time, for instance, for the operation of an air conditioner. Because the vehicle engine is idle the coolant compressor and the required ancillary equipment such as various fans or ventilators must be operated with an alternative source of power.

Air conditioners are known which have, in addition to the compressor operated by the vehicle's engine, an electrically operated compressor in the coolant circuit that takes over the circulation of coolant in standstill operation; their functioning is not substantially different from normal operation, except that a different compressor circulates the coolant. At least two motor-driven fans are provided in such air conditioners, one for the cooling airflow (fresh air or recirculated air) supplied to the vehicle interior and flowing through the evaporator, and one for the condenser cooling airflow (fresh air).

Also known are air conditioners that are not integrated into the air conditioning system for normal driving conditions, but are available as a largely independent system. Such air conditioning systems, also known under the term “stand-alone air conditioners,” likewise have a coolant circulation by means of an electrically driven compressor and two electrically operated fans, one for the cooling airflow (fresh air or recirculated air) supplied to the vehicle interior and flowing through the evaporator, and one for the condenser cooling airflow (fresh air). Such a unit leaves something to be desired.

SUMMARY OF THE INVENTION

The problem of the invention is to provide an improved air-conditioning unit, in particular a stand-alone unit for standstill operation. This problem is solved by an air conditioning unit with the characteristics of claim 1. Advantageous implementations are the subject matter of the subordinate claims.

According to the invention, an air conditioning unit for stand-alone operation, particularly for a motor vehicle or a commercial vehicle, is provided with a coolant circuit, in which are arranged a compressor, a condenser, and an evaporator for cooling down the air to be conditioned, that has a single fan for the heat dissipating air and for the air for cooling the interior that transports the air in part through the condenser and in part through the evaporator, i.e., in contrast to conventional devices, the fan or the blower is eliminated. Because only one fan is provided, the unit can be constructed more compactly, even if in conjunction with a conventional air-conditioning system all of the components, particularly the compressor, the evaporator and the condenser, must be provided twice.

A single power controller is provided to control the fan motor, so that the control is simplified relative to conventional devices with a fan and a blower.

The fan is preferably a two-duct fan, so that the air conveyance amounts satisfy the requirements on both sides. The fan is preferably symmetrically constructed, with the air conveyance amounts on both sides being essentially the same. Due to the provision of a two-duct fan, the normal construction of the air duct system for intake air can be maintained, i.e., only fresh air from the environment is supplied to the condenser, and depending on the requirement (or temperature), fresh air and/or circulating air is supplied to the evaporator via appropriate ducts. Such a linkage is particularly useful for the frequently occurring case of a correlation between the air flow required through the evaporator and condenser.

Alternatively, a separation wall that separates airflow to the condenser from airflow to the evaporator can be provided downstream of the fan. A flap can be provided downstream of the fan for distribution of air to the condenser and to the evaporator as required.

The air conditioning unit is preferably operated exclusively electrically, for which the electric power can be provided via the normal electrical system. In particular for longer standstill periods, however, an external power supply, for example, a connection to the power grid, a supplementary battery or via an auxiliary engine-driven generator is.

The air conditioning unit is preferably arranged in the roof area of a motor vehicle, especially a truck. Only a few other components must be provided in this area, i.e., sufficient space is normally available. Since it is only necessary to lead electric cables for power supply and control to the air conditioning unit, there are no problems with supplying power to or controlling the air conditioning equipment.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention will be explained in detail below on the basis of three embodiments, in part with reference to the drawing. In the drawing:

FIG. 1 shows a schematic representation of the first embodiment, and

FIG. 2 a schematic representation of the second embodiment.

DETAILED DESCRIPTION OF THE INVENTION

According to the three embodiments described below, a stand-alone air conditioning unit 1, which is operable essentially independently of the motor vehicle engine and is therefore suitable for stand-alone operation, i.e. suitable for operation with the vehicle engine not running, has a coolant circuit with a compressor (not shown), an evaporator 2 serving for air cooling and a condenser 3 cooled by outside air for circulating coolant. A single fan 5 driven by a fan motor 4 is responsible for moving the air, i.e., the recirculated and/or fresh air to be supplied to the vehicle interior and the fresh air for cooling condenser 3, with the fan motor 4 being regulated via a power controller 6. That is to say, one fan 5 takes on both the role of a conventional fan (at the evaporator) and a blower (for the condenser).

Air conditioning unit 1 is arranged in the roof area of a truck, independently of the air-conditioning system that handles the air conditioning under normal driving conditions. The control of air conditioning unit 1, and in particular that of the compressor and of fan motor 4, depends on the requirement for cooling capacity, but the existing amount of power, i.e., the charge state of the battery for stationary air-conditioning must also be taken into consideration.

According to the first embodiment presented in FIG. 1, fan 5 has a single impeller 7 that is arranged on the motor shaft. The air drawn in from the interior and the environment by the rotation of impeller 7 through a common intake air duct system is distributed as needed to the vehicle interior with fully open ducts/vents and in particular, relatively uniformly to evaporator 2 and condenser 3, which is accomplished via a separation wall 8 directly downstream of impeller 7 that separates the evaporator air duct, i.e. the air duct leading to the vehicle interior, from the condenser air duct, i.e., the air duct leading to the outside. The composition ratio of recirculated air and fresh air is regulated with the aid of flaps (not shown).

According to the second embodiment shown in FIG. 2, fan 5 is constructed with two ducts, i.e., there are two impellers 7 a, 7 b arranged on the motor driven shaft of fan motor 4, for which reason the two impellers 7 a, 7 b rotate at the same speed. Due to the separate intake, impeller 7 a, which is assigned exclusively to condenser 3, can supply only fresh air and impeller 7 b, which is assigned to evaporator 2, only fresh air and/or recirculated air. A mixing of the air streams will not occur.

In accordance with the third embodiment, which resembles the first embodiment, a regulated flap, which distributes the airflow to the evaporator and the condenser as needed, is arranged downstream of the fan. Corresponding to the first embodiment, a common air intake system is provided, which enables the supply of fresh and/or recirculated air. The composition ratio of fresh and recirculated air is regulated as in the first embodiment with the aid of flaps. 

1. An air conditioning unit for stand-alone operation for a motor vehicle comprising a coolant circuit in which are arranged a compressor, a condenser and an evaporator for cooling the air to be conditioned, the air conditioning unit including a single fan for heat-dissipating air and for air for cooling the interior, wherein the fan conveys the air in part through the condenser and in part through the evaporator.
 2. The air conditioning unit according to claim 1, wherein a single power controller is provided for power for a fan motor assigned to the fan.
 3. The air conditioning unit according to claim 1, wherein the fan is a two-duct fan.
 4. The air conditioning unit according to claim 3, wherein the fan is symmetrically constructed.
 5. The air conditioning unit according to claim 1, wherein a separation wall that separates air flow to the condenser from air flow to the evaporator is provided downstream of the fan.
 6. The air conditioning unit according to claim 5, wherein at least one flap to regulate air distribution to the condenser and the evaporator is provided downstream of the fan.
 7. The air conditioning unit according to claim 1, wherein an air duct system through which both outdoor air and recirculated air can be supplied to the fan is provided for intake air.
 8. The air conditioning unit according to claim 1, wherein the air conditioning unit is exclusively electrically operable.
 9. The air conditioning unit according to one claim 1, wherein the motor vehicle has a roof area, and the air conditioning unit is arranged in the roof area.
 10. The air conditioning unit according to claim 2, wherein the fan is a two-duct fan.
 11. The air conditioning unit according to claim 10, wherein the fan is symmetrically constructed.
 12. The air conditioning unit according to claim 2, wherein a separation wall that separates air flow to the condenser from air flow to the evaporator is provided downstream of the fan.
 13. The air conditioning unit according to claim 12, wherein at least one flap to regulate air distribution to the condenser and the evaporator is provided downstream of the fan.
 14. The air conditioning unit according to claim 9, wherein the air conditioning unit is arranged in the roof area of a truck. 